What kind of detectors will Webb have?
Webb will have two types of detector arrays (SCA): visible to near-infrared arrays with 2,048 x 2,048 pixels, and mid-infrared arrays with about 1,024 x 1,024 pixels. Several detectors will be built into mosaics to give a larger field of view. NIRCam, NIRSpec and FGS-TFI will use Mercury Cadmium Telluride (HgCdTe) detectors made by Teledyne Scientific & Imaging. MIRI will employ arsenic doped silicon (Si:As) detectors produced by Raytheon. • What is the operating temperature of the telescope and the instruments? The large sunshade will protect the telescope from heating by direct sunlight, allowing it to cool down to a temperature below 50 Kelvin (equal to -370 degree F, or -223 degree C) by passively radiating its heat into space. The definition of the Kelvin temperature scale is that 0 K is “absolute zero,” the lowest possible temperature. Water freezes 32 degree F, 0 degree C or about 273 K. The near-infrared instruments (NIRCam, NIRSpec, FGS-TFI) will work at about 39 K (-389 degre
